May 7, 1907: The constitution is amended, changing the presidential term from two years to four.

July 10, 1914: Liberia declares neutrality at the outset of World War I.

At the time that war breaks out in Europe, Germany is Liberia's strongest trading partner, and Liberia is reluctant to declare war against a nation to which its economy is so closely tied.

May 8, 1917: Pressured by Great Britain and the U.S., Liberia withdraws neutrality and declares war on Germany.

Within the year, Germany will retaliate against Liberia's declaration of war by shelling the capital, Monrovia. The Liberian economy is subsequently crippled when the country loses its great economic ally.

1926: Firestone Tire and Rubber Company opens a rubber plantation on land granted by the Liberian government.

The agreement grants Firestone the right to lease one million acres of land for 99 years and to exploit any gold, diamonds, and other minerals found on that land.

April 28, 1929: Booker T. Washington Institute is founded by a group of American missionary and philanthropic groups, including the American Colonization Society.

Modeled after Washington's Tuskegee Institute in Tuskegee, Alabama, BWI is the first formal vocational institution established in Liberia. Like its American counterpart, it emphasized vocational training in such areas as agriculture, auto mechanics, carpentry, and masonry.

March-December 1930: A League of Nations report exposing forced-labor practices in Liberia leads to the president's resignation.

The Liberian government comes under international censure for allowing a system of forced labor "hardly distinguishable from slavery." Implicated in the scandal, President Charles D.B. King resigns on December 3 after pressure from the Liberian legislature.

1936: Forced-labor practices are abolished.

1943: U.S. president Franklin D. Roosevelt stops in Liberia on his North African tour to visit U.S. troops.

Liberia views Roosevelt's visit as a symbol of its strong relationship with the United States, and as confirmation that the U.S. will be a source of support and aid to Liberia.

January 3, 1944: William V.S. Tubman is inaugurated as president.

President Tubman pursues a policy of national unification to draw the indigenous people into the state and society, formally establishing laws to rid Liberia of practices that favor those of settler descent. He encourages economic development through foreign investment, deepened political and economic relations with the U.S., and begins to transform Liberia into a modern African state. Under him, Liberia becomes a founding member of the Organization of African Unity and the United Nations.

January 27, 1944: Liberia enters World War II, declaring war against Germany and Japan in support of the Allies.

1951: Liberia and the United States sign a Mutual Defense Assistance agreement.

June 27, 1955: Tubman crony-turned-political opponent S. David Coleman and his son John are hunted down and killed by Liberian soldiers for allegedly plotting to overthrow Tubman.

The Coleman funeral is meagerly attended, as people are afraid of being considered Coleman sympathizers.

1955: The constitution is amended to allow President Tubman to remain in office well beyond the two-term limit.

August 1957: The U.S. erects a Voice of America relay facility, one of several U.S. communications facilities to be placed on Liberian soil during the Cold War.

1962: The U.S. Peace Corps program begins in Liberia.

The U.S. government agency's program will run for nearly 30 years in Liberia, until 1990 and the outbreak of civil war. Peace Corps service to Liberia has not yet resumed.